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Cassowary (theropod) headgear



Ben Creisler
bcreisler@gmail.com


Just in time for American Thanksgiving, a paper about a giant living
bird. And just think--if Columbus had landed in New Guinea, we'd be
eating cassowaries today....and REAL yams (not sweet potatoes labeled
as "yams").



Darren Naish & Richard Perron (2014)
Structure and function of the cassowary's casque and its implications
for cassowary history, biology and evolution.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2014.985669
http://www.tandfonline.com/doi/full/10.1080/08912963.2014.985669#.VHdmOzHF_To

Cassowaries (Casuarius) possess a cranial casque, sheathed by keratin
and composed of modified cranial bones. We combine data and hypotheses
on three areas of cassowary research. First, we present novel
observations on casque anatomy. The bony core is fragile,
incorporating a mass of trabeculae anteriorly and an empty space
posteriorly. Secondly, we use these observations to evaluate
hypotheses of casque function. Implications that the casque evolved
within the context of activities involving percussive actions are
unlikely and observations that might support these hypotheses are
absent. It is most likely that the casque serves a sociosexual role
and functions in visual and acoustic display. The similarity in casque
form between males and females, combined with male parental
investment, makes it plausible that the extravagant structures present
in cassowaries evolved within the context of mutual sexual selection.
Thirdly, we combine morphological, molecular and geological evidence
to provide a new phylogenetic history for cassowaries. We suggest that
cassowaries invaded New Guinea in at least two waves and provisionally
regard crown–cassowaries as a geologically young, post-Pliocene clade.
We provide these hypotheses as areas requiring discussion and urge
other workers to test our ideas with new data on cassowary anatomy,
behaviour and genetics.